A senior World Health Organization (WHO) official said on Friday that 75 medics in the Democratic Republic of Congo had been infected with Ebola and 17 of them had died since the current outbreak started there.

Ebola was thought to be circulating months before the outbreak was first declared by Congolese officials on May 15, meaning many medics were exposed to the disease before they even knew it was present. Even now, health officials say supplies of the basic gear to protect themselves like gloves and masks are running short. 

"It is a really high price that the system, the healthcare system, is paying, because we don't have enough of healthcare workers in DRC," a WHO emergency director, Marie Roseline Belizaire, told a press conference by video link from eastern Democratic Republic of Congo.

Congo has one of the lowest densities of healthcare workers relative to the population, with only about 11 per 10 000 people, WHO data shows. Belizaire said China and Uganda were sending medical teams to the country.

The WHO is giving psychological support to some medics who were too scared to treat patients, having watched many of their colleagues fall ill, she added.

"When they are explaining to you how they live it, how they were infected ... (it) can break your heart."